Well, you could change your screen name to Broken Rubber…
My only sibling is 18 years, 29 days younger than I.
My brother is 5 years younger than me, then another 5 years to my sister and 7 years to my youngest brother.
I said Eisenhower administration because I was born in 1959 and my sister in 1960, so it’s a time period that covers both years. If it’d been in the same decade, though, I would’ve just said the decade.
I’m #2 of 6.
-
Older sis
-
after 15 mos came me.
-
4 years later comes little sis
-
2 years after that is another little sis
-
6 years later came final little sister x 2 with a set of twins. I was 13 when they were born.
That final try for a boy really bit 'em in the ass, eh?
11 years. I have one sibling, my sister. My parents are actually still married to each other.
And we were both surprises.
Okay, I get it when you’re nineteen…but when you’re 31?
Including my adopted sister, 3.5 years. Not including, 7 years.
3 years.
Thirteen months older and thirteen months younger.
My parents (Mom’s Catholic) had six kids in 5.5 years (no twins) during the Kennedy and Johnson administrations. They also raised a cousin as their own and took in a foster son when he was a teen.
I’m the youngest of three, 2 years and 11 months younger than my brother to the day. He’s two years, ten months, and three weeks younger than my big sister. 
3.22739726027 years here
my siblings an I are: 20 months, 22 months, 7.5 years. ('69, '71, '73 and '81)
I’m not sure what’s surprising. Most parents don’t have one baby/year then quit.
Again, I’m at the contrary surprised that the OP allowed several answers for a difference of less than 3 years, and only one for 3+ years.
3+ spread is airily common. Many of our friends had kids three years apart. Ore common than less than three.
Ten kids in our family, Spaced out evenly over twenty years.
Older brother to me - 3 years 4 months
Me to younger brother - 2 years 5 months
There are four of us, total, and since I managed to come along just ahead of the school cutoff, we were three years apart in school.
I have a brother who is a week shy of 26 months older than me and a sister who is 5 years and a few days younger, which places me in the relatively uncommon category of 2-2.5 years (if not as much as the 3+ year category; less than 1 year is also more that I would expect given that at least 9 months are needed between births).
I have two sisters, 5 1/2 and 7 1/2 years younger than I. The baby was unplanned. ETA: I’m an 80s baby and they are 90s babies.
Spacing of 3-6 years is quite common in the rest of my family and among most people I know. The only people I know who have 2 kids in less than 4 years are quite religious and/or passionate for some reason about close spacing.
I am close with each of them but they have never liked each other much and barely speak these days, they’ve never even had a mutual friend their whole lives… Sibling relations are mostly to do with personality IMO, closer spacing does not guarantee any sort of friendship. I’ve done a lot of childcare, and I’ve always known I’d like my own kids to be 3+ years apart - I don’t want two babies in diapers at the same time.
There were four of us born within three years and nine months, with no twins or triplets. And a miscarriage the previous year. My younger brother is more than 5 years younger, though.
Mormon, in the early 60s, funny you would ask.
My sister and I were born 19 months apart when my parents were WAY too young to be having kids. Then there was a stillborn 3 years later due to a form of Brittle Bone believed at the time to be genetic. So no more kids for another 3 years, when my parents decided to have 4 more a year or two apart.